Vornado MD1-0001 Replaceable Humidifier Filters 2-pack: At 7.25″H x 9.5″L x 1.5″W this pack of two (2) wick filters is designed to fit select Vornado Humidifiers. The filter must have the correct height width thickness and material for maximum performance. Competitors often advertise their filters will work with Vornado humidifiers but these filters don’t always fit properly therefore the humidifier will not work effectively. Vornado wicks are developed from the highest quality materials that work to absorb the maximum amount of water while filtering the circulating air. Competitor brands are made of different materials not designed for Vornado humidifiers. These humidifier replacement filters part number MD1-0001 (same as MD1-0002) work with models Evap3 Evap1 Model 30 and Model 50.